Problem: Simplify the following expression: $k = \dfrac{60yx - 50x}{20x^2 - 50zx} + \dfrac{60zx}{20x^2 - 50zx}$ You can assume $x,y,z \neq 0$.
Explanation: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{60yx - 50x + 60zx}{20x^2 - 50zx}$ The numerator and denominator have a common factor of $10x$, so we can simplify $k = \dfrac{6y - 5 + 6z}{2x - 5z}$